Electrical thermomotive device



March 10, 1942. c; w. MUSSER 2,275,795

ELECTRICAL THERMO-MOTIVE DEVICE Filed March 6, 1941 Ennentor Witness I pattorney Patented Mar. 10, 1942 UNITED STATES PATENT OFFICE} 2,275,795ELECTRICAL THERMOMOTIVE DEVICE Charles W. Musaer, Omaha, Ncbn, aaaignorto Jubilee Manufacturing 00;, Omaha, Nebn, a corporation of NebraskaApplication March 6, 1941, Serial No. 381,969 8 Claims. (Cl. 200-138)The present invention relates to the electrical art and moreparticularly to electrical circuit breakers and has for an object toprovide a breaker which may be manually or otherwise closed inaccordance with the particular en-- vlronment in conjunction with whichthe device is used and which is so constructed that it may be repeatedlyused.

Another object of the invention is to provide a thermo-motive device forsaid purpose of economical manufacture which is of permanent, durablecharacter.

A still further object of the invention is to provide a circuit breaker,the circuit opening action of which is comparatively very rapid. t Otherand further objects and advantages of the invention will be obvious tothose skilled in the art from the following detailed descriptionthereof.

In the drawing:

Figure l is a side elevation of the new device mounted on a fragment ofa block of insulation, certain movable'electrodes employed being in aclosed contacting position with respect to each other.

Figure 2 is a similar view certain portions of the new device being insection, said electrodes being in an open position. I

Figure 3 is a top plan view of the invention and showing the latterincluded in a diagrammatically illustrated, energized electrical circuittogether with an incandescent light bulb.

As heretofore practiced in the art, especially in dwelling housesmeltable fuses have been commonly employed in electrical circuits forbreaking the later at times when short circuits have occurred, saidfuses requiring replacement often by people unfamiliar with theelectrical art thereby causing delay, danger and injury to saidpersons,the latter also often inserting new fuses repeatedly in damaged orimproper circuits without repair of the latter, thereby wasting saidfuses unduly, and the present invention aims to obviate said undesirablefeatures of the prior practice.

Referring now to the drawing for a more particular description llindicates a fragment of a block of insulating material which ispreferably stationary such as when attached to thewall of a switch boxwithin a dwelling house or when attached to the dashboard or othersuitable portion of an automobile or the like having electricalinstrumentalities for which protection against abnormal electricalcurrents is desired.

The new device includes a thermo-motive electrode generally indicated atH and which preferably consists of a bi-metallic disk of concavoconvexcontour incross section, the half portion I! of which is formed of oneselected metal and the other oppositely disposed half portion i3 thereofconsisting of a different metal, said electrode portions i2 and I3 beingsuitably Joined together in a manner whereby the disk is suflicientlythin to be flexible for later described purposes and sufliclently thickto resist a selected degree 01' heat applied to said disk.

The disk H as thus described is normally of an initial form-sustainingcharacter and while a bi-metallic disk is preferred it will beunderstood that any electrode formed of one or two pieces of metal whichwill become suitably deformed for later described purposes, uponbecoming heated sufliciently, may be employed in lieu of said preferredbi-metallic construction.

As .best shown in Figure 2, preferably the medial portion of the disk issecured by means of a bolt or screw electrode H to said insulation it, anut or the like it preferably being disposed between said block and saiddisk. 4

An electrode it having an inwardly oil-set detent portion or hook i1 isdisposed in electrical contact with said disk and secured to the latterby means of. a rivet i8 preferably adjacent the perimeter of said diskand it will be understood that said disk, for certain uses, may beelongated in lieu of the circular disk specifically i1 lustrated.

The detent ll is provided with an outwardly flared guide portion i8 forfacilitating engagement of a later described arm under and with saidhook,

An electrode 28 having an arm portion ii is carried by the disk andelectrically insulated from the latter by means of laminations ofinsulating material or washers 22 and 23, said member 20 beingmechanically secured to the disk by means of a rivet or the like 24which also secures said washers together.

The electrode "is preferably formed integral with the arm 2i and ofresilient material such as spring bronze whereby resultant from saidelectrode l6 away from the rivet 24 for permitting said free end of thearm to engage under the hook detent II; whereupon said free end of theelectrode [6 returns to a normal position, as shown in Figure 1, saidelectrodes 20 and I6 then being disposed in electrical contact with eachother.

It will be understood that the above described device may be enclosed,if desired, in a housing or suitable container, in which case the latteris preferably provided with a glass or transparent mica window wherebyan operator may visualize the position of the electrode portions l1 and26 with respect to each other for noting whether or not they are incontact and at times when a housing is employed a knob of insulation orplunger is disposed through a wall of said housing whereby the operatormay place his finger upon said plunger for causing said free end 26 toengage with the detent hook il. As specifically shown in Figure 2, saidknob of insulation 21 is carried by the arm 2! and secured to the latterby means of a screw 28 whereby the operator may readily depress the arm2! by placing his finger or the like on said knob for said purpose andwithout said finger becoming electrifled.

An electrode clip 29 is secured to the rivet 24 for facilitating anelectrical connection between a wire 30, said clip and the metallicrivet 2|, said wire preferably being soldered to the clip as at 3 i.

Similarly a wire 32, as shown in Figure 1, is soldered as at 33 to asecond clip'electrode 34, an end of the latter being mechanically andelectrically attached to the screw electrode H by a suitable means suchas the nut 35.

As thus described at times when the wires 30 and 32 are included in aclosed electrical circuit the current will pass from a source of energythrough the screw electrode H to the medial portion of the disk ii andthrough the electrode i8, arm 2|, rivet electrode 24 and clip 29 attimes when the wire 32 is in electrical communication, as described,with the medial portion of the disk. It will be further noted that forcertain types of use the wire 32 may be electrically connected to thedisk adjacent the perimeter thereof although the disk becomes heated andmore quickly responsive, as later described, at times when the wire 32is electrically connected to the medial portions of said disk.

For certain uses the new device is comparatively minute with respect tothe proportional size thereof specifically illustrated imthe drawing,and it will be understood that the device is so constructed andassembled that the disk becomes deformed resultant from a currentpassing through the disk which is greater than a preselected normaldegree resultant from said disk becoming heated as later described.Manufacture of specimens of the new device are made of a preselectedcapacity to be used in conjunction with and for a certain current.During manufacture the devices are marked "15 A", "30 A", 60 A and thelike for denoting that the devices so marked are of respectively 15,

30 and 60 ampere capacity. For automobile use or when the source ofelectrical energy is a conventional 6 volt battery, said specimens arecorrespondingly and approximately marked for purposes well known tothose skilled in the electrical art.

The capacity of any specimen of the new device to open a circuit attimes when the latter includes more amperage than desired is governed bythe particular construction of a specimen, either by making the disk llthicker or thinner. by the degree of convexity of said disk or the lackof said convexity or by the degree oi the urge provided by the springportion 25 or by the length of the arm 2| with respect tothe hookdetentl1.

Referring to Figure 3 the wire 30 is in communication with the wire 36the latter also being in electrical communication with a utilitarianelectrical instrumentality such as the incandescent'light bulb generallyand diagrammatically indicated at 31, said device 31 being incommunication with a battery 38 or other suitable source of electricalenergy through a wire 39, said battery being similarly connected to thewire 22 througha wire or similar conductor 40 and as thus described itwill be understood that the new invention may be included in thedescribed electrical circuit for protecting the electricalinstrumentality 31 from damage at times when and if the currentgenerated becomes too great for the capacity of the device 31 andgreater than the disk H will carry without deformation.

In operation, assuming that the disk H is mounted to a stationaryobject, at times when electrical current flows through said disk, thelatter becomes correspondingly heated, and assuming that the disk hasbeen constructed to withstand a current of i5 amperes said circuitoperates normally, At any time the amperage of said circuit becomesincreased, by any means, above said selected normal degree, said diskinstantly becomes correspondingly heated proportionally and to a greaterdegree than its capacity to withstand said heat without deformation,thereby causing the perimeter of the disk to be moved in the directionof the arrow 4| and towards the convexed medial portion of the disk, thelatter thereby becoming flatter in side elevation contour and moving thehook detent l1 away from the free end 26 of the electrode 20;

. to move away from the hook I! for breaking the circuit.

At times when the circuit becomes broken it remains open even after thedisk has become cooled said circuit not being reclosable until anoperator is informed, resultant from said breaking, that said circuitrequires repair or adjustment after which said circuit may be manuallyand readily closed. In cases where said operator is inexperienced,should he manually close the electrodes l1 and 28 together and therebyclose said circuitwithout adjustment or repair of the latter, saidcircuit and new, device immediately becomes reopened and prior to damageof the instrumentality 31.

From the foregoing description it is thought to be obvious that anelectrical thermo-motive device constructed in accordance with myinvention is particularly well adapted for use by reason of theconvenience and facility with which it may be assembled and used, and itwill also be obvious that my invention is susceptible of some change andmodification without departing from the principles and spirit thereofand for this reason I do not wish it to be understood as limiting myselfto the precise arrangement and formation of the several parts hereinshown in carrying out my invention in practice except as claimed.

I claim:

1. An electrical device comprising a block of electrical insulatingmaterial, a bi-metallic disk of concavo-convex contour in cross section;said disk being normally of initial term sustaining character, a boltelectrode for attaching a medial portion of said disk to said block, adetent electrode secured to and in contact with said disk adjacent theperimeter of the latter, and a third electrode having a resilient armportion carried by and electrically insulated from said disk, saiddetent and arm electrodes being spaced apart with respect to each otherand adapted to be included in an electrical circuit. the free end 01said arm being adapted to engage in said detent i'or normally closingsaid circuit, said disk being adapted to become deformed at times whenan electrical current greater than a preselected'degree is applied tosaid circuit for releasing said arm from said detent for opening saidcircuit, whereby said disk becomes cooled and assumes its said normalinitial form for reuse.

. 2. An electrical device comprising a bi-metallic disk ofconcavo-convex contour in cross section, said disk being normally ofinitial form sustaining character, an electrode secured to and incontact with said disk adjacent the perimeter of the latter, saidelectrode being provided with 4. In an electrical circuit opener, ametallic disk, oppositely disposed electrodes carried by said diskadapted to be included in said circuit,

. one of said electrodes being in contact with said a detent portion,and a second electrode having a resilient arm portion carried by andelectrically.

insulated from said disk, said electrodes being spaced apart withrespect to each other and adapted tobe included in an electricalcircuit, the free end of said arm being adapted to en,- gage in saiddetent i'or normally closing said circuit, said disk being adapted tobecome deformed at times when an electrical current greater than apreselected degree is applied to said circuit for releasing said armfrom said detent for opening said circuit, whereby said disk becomescooled and assumes its said normal initial form for reuse.

3. In an electrical circuit, a bi-metallic member, two electrodescarried by said member, one oi said electrodes being insulated from saidmember and provided with a resilient swingable arm portion, the otherelectrode being in contact with said member and provided with a detentportion engaged with theiree end of said arm for normally closing saidcircuit through said electrodes, said member being adapted to becomedeformed at times when the electrical current carried "by said circuitbecomes greater than a preselected normal degree, said member andelectrodes being so constructed and assembled that at times when saidmember becomes deformed the r said free end moves away said circuit.

disk and the other electrode electrically insulated from said disk,means for causing said electrodes to normally engage each other forclosing an electrical circuit through said electrodes, said disk andelectrodes being so constructedand assembled with respect to each otherthat at times when said circuit is electrically energized in excess of apreselected degree said electrodes disengage for breaking said circuit.

5. A device, for the purpose described comprising a bi-metallic disk,two spaced apart electrodes secured to said disk, one of said electrodesbeing electrically insulated from said disk and the other in electricalcontact therewith, a metallic spring arm having an end secured to one ofsaid electrodes, means for causing engagement between the free end ofsaid arm and the other electrode, said disk being so constructed that itbecomes deformed when suflicintly heated for permitting disengagement ofsaid arm and said other electrode, said disk being adapted to assume aninitial form upon becoming of substantially initial temperature.

6. An electrical theme-motive device comprising a bi-metallic disk 01'concavo-convex contour irom said detent for breaking in cross section,an electrode secured to and electrically insulated from said disk havinga swingable arm portion disposed across said disk, a detent electrode inelectrical contact with said disk adjacent the perimeter thereof, thefree end or said arm being adapted to engage in said detent, andresilient means for moving said arm away from said detent responsive toa change in the normal cross sectional contour of said disk.

7. A device as described in claim 6 having a knob of electricalinsulating material adapted to .be pressed by an operators finger formoving the free end or said arm into engagement with said detent. v

8. An electrical device comprising a thermomotive electrode, a secondelectrode having a swingable arm portion disposed-across andelectrically insulated from said thermo-motive electrode, a detentelectrode in electrical contact with said thermo-motive electrode, thefree end of said arm being adapted to engage in said detent, andresilient means for moving said arm away from said detent responsive toa change in the normal contour of said thermo-motive electrode.

CHARLES W.

